M1A2 Abrams? Are you sure? Because that would be difficult as hell. Even modern 125mm Russian APFSDS would have hard time penetrating frontal armour of M1A2. For a gun of 100mm calibre, it would require both surprise rear attack and some sheer luck. Today, 100mm guns serve purpose of all-round artilery rather than anti-tank, though Chinese claim to be able to penetrate frontal T-72 armour with their gun.

PS: If it's a copy of Soviet T-12 (and it most likely is, Chinese never bothered with copyrights), then it should have longer barrel ;)

Maybe you could make an attempt at even more realistic economy- such as varied value of currency depending on the power of state's economy? F.e., Gondor's currency being stronger than Rohan's, Dwarven being stable and unchanging etc.

Have you ever considered making possible to play your mod in single player skirmish mode? My internet connection is unfortunately very laggy and I can't really enjoy multiplayer... And I am really interested in playing this mod, introducing modern weaponry in this game could really refresh the gameplay experience.